Conventionally, as an image reading apparatus of this type, an apparatus as shown in FIG. 4 is known. In FIG. 4, an original P is placed on a glass plate 105 as a light transmitting member, then a cover 1 is closed to press the original P against the glass plate 105.
Reference numeral 101 denotes a frame which also serves as an external cover, including constituent elements such as a guide bar 102, a reading unit 110 as image reading means and a holder 107.
The reading unit 110 reads an image of the original P, while the unit, guided by a guide shaft 102, is scanned in parallel to the glass plate 105 by driving rotation of motor 106.
The reading unit 110 includes an LED of three colors (R, G and B) as a light source for irradiating the original, a rod lens array which forms an image from light reflected from the original on a photoreception device of image sensor, and the image sensor. The light source of the three-color LED is sequentially changed and turned on, and the image sensor reads light reflected from the original by each color, thus performs color separation reading.
The reading unit 110 is provided on the holder 107 and thrusted against the glass plate 105. The holder 107 and the reading unit 110 construct the image reading means for performing a scan movement.
A slider 112 is provided on the holder 107. The holder 107 is slidably supported on the guide shaft 102 by the slider 112.
The guide shaft 102 is supported by bearings of the frame 101 at ends and fixed to the frame 101 with screws, thus unrotatably positioned.
The motor 106 as a driving source to move the reading unit 110 along the guide shaft 102 is provided in a lower position of the frame 101.
The frame 101 includes a transmission mechanism to transmit the driving force from the motor 106 to the holder 107 and the reading unit 110. The transmission mechanism has a driving wire 104 and a pulley 103.
The driving wire 104 is fixed to the frame 101 at one end, and supported by deflection means (not shown) at the other end, thus the wire has a predetermined tension. Further, the holder 107 is fixed to the driving wire 104, and the holder 107 is movable along the movement of the driving wire 104.
The driving wire 104 is put around the pulley 103, and the driving force from the motor 106 is transmitted to the pulley 103.
Then, as the driving force from the motor 106 is transmitted to the pulley 103, then the driving force is further transmitted to the driving wire 104 around the puller 103, and the holder 107 and the reading unit 110 move. The reading unit 110 reciprocate-moves in parallel to the glass plate 105 by forward/reverse movement of the driving wire 104 in correspondence with forward/reverse rotation of the motor 106 and the pulley 103.
Further, a mainboard 108 is provided in a low position of the frame 101. A flat cable 111 as a control signal path for the reading unit 110 is connected to the mainboard 108, and a flat cable 113 as a control signal path for the motor 106 and the pulley 103 as drive means is connected to the mainboard 108.
However, in the above-described conventional art, the mainboard 108 is fixed to the frame 101, and the flat cable 111 as a control signal path for the reading unit 110 is connected to the mainboard 108.
Since a large number of signal lines are used in the control signal path of the reading unit 110, the width of wider surfaces of the flat cable 111 is very large. For this reason, the wider surfaces of the flat cable 111 must be parallel to the surface of the glass plate 105 as shown in FIG. 4.
In this arrangement, in a case where the apparatus is of thin type, the glass plate 105 and the flat cable 111 come into contact with each other. Upon movement of the reading unit 110 in, e.g., an arrow B direction in FIG. 5A, the flat cable 111 is moved in a direction opposing friction with the glass plate 105, the flat cable 111 tends to buckle as shown in FIG. 5B.
Further, in the conventional art, as the width of the wider surfaces of the flat cable 111 is large and the cable is provided in parallel to the surface of the glass plate 105, it is difficult to hide the flat cable 111 under a frame portion of the frame around the glass plate 105. The flat cable 111 in the frame 101 is seen and the appearance is poor.